Fractal dimension in CT low attenuation areas is predictive of long-term oxygen therapy initiation in COPD patients: Results from two observational cohort studies

BackgroundSome chronic obstructive pulmonary disease (COPD) patients develop hypoxemia with disease progression, with some even requiring long-term oxygen therapy (LTOT). Lung function, especially diffusing capacity, and the annual decline in PaO₂, are reported to be predictive factors of chronic respiratory failure. However, the association between lung morphometry evaluated using computed tomography (CT) images and LTOT initiation is unknown.MethodsWe retrospectively evaluated the relationship between clinical indices, including pulmonary function, body mass index (BMI), and CT parameters, at baseline and LTOT initiation in two prospective COPD cohorts. In the Nara Medical University cohort (n = 76), the low attenuation area (LAA) and its fractal dimension (fractal D) were adapted as the indices for parenchymal destruction in CT images. The association between these CT measurements and LTOT initiation was replicated in the Kyoto University cohort (n = 130).ResultsIn the Nara Medical University cohort, lower BMI (hazard ratio [HR]:0.70, p = 0.006), lower % diffusing capacity (%DLCO) (HR: 0.92, p = 0.006), lower %DLCO/VA (HR, 0.90, p = 0.008), higher RV/TLC (HR, 1.26, p = 0.012), higher LAA% (HR: 1.18, p = 0.001), and lower fractal D (HR: 3.27 × 10^?8, p < 0.001) were associated with LTOT initiation. Multivariate analysis in the Kyoto University cohort confirmed that lower %DLCO and lower fractal D were independently associated with LTOT initiation, whereas LAA% was not.ConclusionFractal D, which is the index for morphometric complexity of LAA in CT analysis, is predictive of LTOT initiation in COPD patients.     

Is the Evaluation of the Global Quality of Life Determined by Emotional Status?

The present study investigated relationships between global QOL perceptions and well-being dimensions. Especially our goal was to evaluate the impact of generally recognised four broad dimensions of QOL (physical, functional, social and emotional well-being) on global QOL perceptions, additionally person's satisfaction with life achievements and economical situation were measured as well as social demographic variables. The subjects were a representative sample of Finns (n = 4613, from 25 to 65 years) of the FINRISK-97 study. Correlation coefficients and models of hierarchical regression indicated that physical, functional and social well-being as well as sociodemographic factors and satisfaction with life achievements are important factors of global QOL perceptions both among males and females. However percentages of variances explained with these measures were only moderately high, ranging from 1 to 10%. After measures of emotional well-being were entered into the models of hierarchical analyses of regression, variances explained grew dramatically over 20%. The results of the study indicated that global QOL judgements are likely to be based on current emotional state.     

水平管中气固两相流的混沌特征分析

对水平管密相气力输送系统的混沌动力学行为进行了分析，对煤粉浓度信号时间序列的最大Lyapunov指数和关联维数进行了计算。结果表明，系统的最大Lyapunov指数均大于零，这充分说明煤粉在水平管中的密相气力输送存在混沌特征。从密相移动床流区到沉积层流区，混沌吸引子由大变小，关联维数从1．5359减小到1．0764。说明从密相移动床流区到沉积层流区，流体系统运动的混沌程度逐渐减弱。     

Mass-fractal-like microstructure and proton disorder in nanostructured pseudoboehmite: a neutron-scattering study

Boehmite (γ-AlOOH) is often the initial product in sol–gel syntheses of high surface-area alumina powders. Depending on the processing routes, the microstructure of an AlOOH powder can be tailored to exhibit nanometer particle size and complex interfacial OH sites. Neutron small-angle scattering (SANS) and spectroscopy were utilized to characterize the microstructure and hydrogen vibrations of a nanostructured pseudoboehmite and a highly crystallized boehmite powder. The SANS data reveal a mass-fractal-like microstructure in pseudoboehmite. The vibrational bands of hydrogen atoms in pseudoboehmite are broad, which is indicative of a high degree of proton delocalization and disordered OH sites.     

神经网络分析方法用于心脏病诊断的研究

神经网络可以很好的拟合任意的非线性函数。我们从 QRS波群的高频三维频谱中提取出一些定量的特征参数 ,用神经网络的方法对这些参数进行有监督的学习训练 ,最终能在由这些特征参数张成的 m维空间中构建出一个 m维的曲面来区分病人和健康人的 QRS波群高频三维频谱 ,从而使得训练后的网络能基于 QRS波群的高频三维频谱自行诊断出病人和健康人     

Supraspinal effects on the fractal correlation in human H-reflex

In our previous study, -type power spectrum with the spectral exponent significantly greater than zero was found in the variability of soleus H-reflex amplitudes. This result indicated that the H-reflex variability was time-correlated owing to fractal characteristics. Furthermore, it was also suggested that the fractal characteristics were generated at the spinal level. The purpose of the present study was to investigate whether the fractal nature of the H-reflex variability was influenced by the loss of supraspinal input. Six healthy normal subjects and seven patients with spinal cord injury participated in this study. Soleus H-reflexes were evoked every l s from both legs simultaneously (stimulation intensity: motor threshold) and 1050 successive amplitudes of the H-reflex were recorded. The H-reflex sequence evoked from each leg was analyzed by coarse graining spectral analysis to calculate the spectral exponent . The value of was used to evaluate the level of time-correlation (fractal correlation). Cross-spectral analysis was used to evaluate the degree of synchronization between the H-reflex sequences evoked from both legs. The values for normal subjects (0.84±0.33, left leg; 0.88±0.34, right leg) were significantly greater (P<0.001) than those for patients (0.31±0.18, left leg; 0.32±0.14, right leg), suggesting that the H-reflex sequences for normal subjects were more time-correlated than for patients. In the frequency range less than 0.2 Hz, the coherence of both legs was high (0.41±0.14) for normal subjects as compared to 0.20±0.12 for patients (P<0.005). In this frequency range, the phase was almost 0 rad for normal subjects, indicating that the H-reflex variabilities of both legs were synchronized. These results suggested that (1) the strong fractal correlation observed in the H-reflex sequences for normal subjects was associated with supraspinal input, and (2) such supraspinal input had equal influence on the reflex arcs of the soleus of both legs.     

正常国人腰间盘纤维软骨粘弹性实验研究

研究了正常国人急性外伤致死的成人新鲜尸体10个腰间盘L3-4、14-5纤维软骨的力学性质。以一维拉伸的方法得出了L3-4、L4-5腰间盘纤维软骨的破坏载荷、伸长比、Lagrange张应力、Lagrange张应变等数据。以多项式，用回归分析方法得出椎间盘L3-4、L4-5纤维软骨的应力-应变关系表达式及应力-应变曲线。还对椎间盘L3-4、L4-5纤维软骨进行拉伸应力松弛、蠕变实验。得出了椎间盘L3-4、L4-5纤维软骨的归一化应力松弛函数、蠕变函数G(t)、J(t)表达式。以冯元桢教授的软组织大变形准线性理论，构建了L3-4、L4-5椎间盘纤维软骨的松弛函数K(λ，t)=G(t)T^(e)(λ)的表达式，对实验结果进行分析讨论。